Ultrafine Aerosol Dynamics Module for Modal Aerosol Dynamic Model for Europe A contribution to subproject GLOREAM

The treatment of nucleation is an extremely important part of any atmospheric aerosol model. Nevertheless, formulations of binary nucleation rates of water and sulphuric acid have not been in good agreement with measured nucleation rates. Additionally, the understanding of the importance of nucleation on a regional scale is still limited. New nucleation mechanisms, e.g. ternary nucleation of sulphuric acid-ammonia-water, have been recently suggested as a possible explanation of the observed atmospheric nucleation events. These mechanisms should be parameterised and tested in different aerosol dynamical models to investigate their applicability and to compare them with atmospheric measure-ments. Therefore, we have continued the development of the Modal Aerosol Dynamic model for Europe (MADE) including an improved representation of the nucleation and the freshly nucleated particles. Preliminary tests in a zero and one-dimensional version of MADE showed that several changes to the numerical solution method and the modal structure were necessary. The results are compared with results of a sectional model